Almost half the energy expended by a silicon microchip during its manufacture and lifetime is spent in producing the silicon wafer material, and another quarter is spent during the operating lifetime of the microchip. A technique that reduces the energy associated with fabrication of the silicon material and power consumption during operation will reduce the overall cost of the silicon microchip integrated circuit.
Power consumption during operation can be reduced using silicon on insulator (SOI) technology. The use of SOI technology not only results in a lower power consumption but also increased speed of operation of integrated circuits due to a reduction in stray capacitance. For SOI structures, thin layers of silicon on insulator can be fabricated using several well known techniques such as separation by implantation of oxygen (SIMOX), separation by plasma implantation of oxygen (SPIMOX), silicon on sapphire (SOS), bonded wafer processes on silicon, and silicon bonded on sapphire.
Bonded wafer processes on silicon involve technologies to bond monocrystalline silicon materials onto semiconductor wafers and oxidation processes to form the semiconductor on insulator. In these technologies, a portion of one or both of the bonded wafers is removed, typically, by polishing methods. Another process to remove large portions of a bonded wafer uses a “Smart cut” technology. “Smart cut” technology generally refers to a process in which a material is implanted into a silicon substrate to a particular depth and ultimately utilized to crack the substrate.
There continues to be a need to provide fabrication processes and structures to reduce the overall cost for a silicon microchip integrated circuit.